Introducing a brand-new, multimillion-dollar intergalactic adventure film based on a French comic book strip during a summer box office dominated by superheroes and sequels may be considered a big risk to take by an independent filmmaker.

But French director Luc Besson was so confident in his vision for adapting the Valerian and Laureline sci-fi comics into a film, he took his script and sketches to buyers at the Cannes Film Festival three years ago with the hopes of securing funding for the $150 million project.

Director/producer/writer Luc Besson attends the "Valerian and the City of a Thousand Planets" panel on Day 1 of Comic-Con International in San Diego, July 21, 2016.

"They all raised their hands because they loved the script, so we had almost 90 percent of the funding in one day," Besson told Reuters.

Set in the 28th century where humans and aliens have found a home on the space station Alpha, Valerian and the City of a Thousand Planets follows two space agents, the cocky Valerian (Dane DeHaan) and the spirited Laureline (Cara Delevingne), trying to uncover the origins of a mysterious force.

They journey through the different environments and diverse population of Alpha, known as the city of a thousand planets where species include sea monsters, organic robots, winged reptilians and thuggish, bug-eyed ogres.

The film comes out in theaters on July 21 and is the fruition of Besson's nearly 50-year obsession with the comic strip he discovered at age 10, setting him on a path to make films such as The Fifth Element and Lucy.

Lots of competition

The stakes are high for Besson's EuropaCorp film studio as Valerian enters a box office saturated with superhero films such as Wonder Woman and Spider-Man: Homecoming and sequels such as War for the Planet of the Apes and Despicable Me 3.

Still, the director didn't consider it a gamble.

"You take risks when you do a first-time director movie at $8 million and no cast. That's a gamble," Besson said, adding that Valerian's theatrical rights had already been bought across nearly 120 countries.

Early reviews for the film have been mixed, with critics praising the vibrant visuals but criticizing the plot and performances.